Comment 2 for bug 801244

Well coded and coded defensively with good input validation. verify_interface() could be better in the face of no ip and no ifconfig, but we always have those, so no biggie. Would be nice if it used 'set -e' in /usr/sbin/vblade-persist, but I don't see anything that is wrong.

Feel free to promote, but note the dependency on runit which is still in universe (I don't see a bug for it either).